This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The goals of the TrialNet Natural History Study of the Development of T1D are to both gain information about the pathogenesis and natural history of T1D and to facilitate the recruitment and assessment of individuals who might qualify for T1D prevention trials. Importantly, the information obtained from this study will serve to enable the development and implementation of prevention trials. The design of the TrialNet Natural History Study of the Development of T1D as described below is intended to achieve these goals.